Cylinder head castings to be used in internal combustion engines contain 4 to 8 cavities or combustion chambers, and the lower surface of the head casting is adapted to be joined to the cylinder block of the engine. After the casting operation, the upper surface of the head casting, as well as the sides and ends of the castings, is ground to remove parting lines, flash, flow pins, gating, etc., from the casting. In the past, the practice has been to manually gring away the projecting flash and parting lines, while in the case of flow pins, the pins were manually knocked off by hammers and then ground down manually.
While automatic grinding of the cylinder head castings is desirable, no fixture or jig has been developed in the past which would properly level the casting.
An automatic grinding machine includes one or more grinding wheels which operate in a fixed plane or position for a given size casting. If the casting is not precisely level when it is passed through the grinding machine, vaaious portions of the casting may be ground too deeply, while other portions may be ground too lightly so that the casting irregularities, i.e., flash, parting lines, gating, etc., will not be completely removed. As all the outer surfaces contain casting irregularities, the outer surfaces cannot be used as reference planes for the grinding operation, and the casting cannot be precisely leveled by merely resting it on one of its outer surfaces. Because of these problems in leveling the casting in both a longitudinal and transverse direction, automatic grinding has not been successfully applied to cylinder head castings.